Aerodynamic Characteristics of a Slender-Body Ejecting a Supersonic Jet

Abstract

“Nose-first entry” flight has been proposed as one of the methods of return flight of a vertical take-off and vertical landing reusable rocket using engine thrust for vertical landing. In this flight method, the engine exhaust jet opposes the free-stream during the turnover maneuver and landing, causing concern that the aerodynamic force acting on the vehicle changes due to a complicated flow field made by the interaction between the exhaust plume and free-stream. A slender-body model that can eject a supersonic jet was studied in a low-speed wind tunnel to characterize the flow. The aerodynamic forces were measured, and the flow pattern on the surface of the model was visualized using the oil-flow technique. The results indicate that the axial force decreases in the low angle-of-attack region, and the rate of change in the axial force is much smaller compared with previous studies in which the jet is ejected from a blunt configuration. The surface flow pattern is also changed by the jet ejection. However, the normal force and pitching moment do not change. Therefore, the influence of the jet strongly depends on the vehicle shape, and the aerodynamic characteristics are restrictive in slender-body shape rockets.